1. Technical Field
The present invention relates to a piezoelectric element having a first electrode, a piezoelectric body layer and a second electrode, and a liquid ejecting head and a liquid ejecting apparatus which include the piezoelectric element.
2. Related Art
A typical example of a liquid ejecting head mounted on a liquid ejecting apparatus includes an ink jet type recording head which ejects ink droplets from a nozzle. Although configurations of the ink jet type recording head are diversified, for example, there is a configuration in which the ink droplets are ejected by a piezoelectric element being driven. The piezoelectric element is provided on a vibration plate configuring one surface of a pressure generation chamber. The vibration plate is deformed by the driven piezoelectric element. Thereby, the pressure in the pressure generation chamber is increased and thus the ink droplets are ejected from the nozzle communicating with the pressure generation chamber.
Further, the piezoelectric element mounted on the liquid ejecting head or the like includes, for example, a deflecting vibration mode of the piezoelectric element configured such that a piezoelectric body layer formed of a piezoelectric material that exhibits an electrical-mechanical conversion function is interposed between a first electrode and a second electrode.
In the above configuration of the piezoelectric element, for example, due to moisture or the like, a leakage current occurs between the first electrode and the second electrode, and thereby there is a possibility that the piezoelectric body layer may be destroyed. In order to suppress such destruction of the piezoelectric body layer, for example, there is a piezoelectric element which is covered with a protection film. Further, for example, a surface of the piezoelectric body layer is covered with an upper electrode (second electrode), so that the occurrence of the leakage current between a lower electrode (first electrode) and the upper electrode (second electrode) is suppressed (refer to JP-A-2009-172878).
As is in the invention according to JPA-2009-172878, by covering the surface of the piezoelectric body layer with the second electrode, it is possible to suppress the destruction of the piezoelectric body layer. However, as shown in FIG. 4 of JP-A-2009-172878, there may be a case where an exposure portion of the piezoelectric body layer needs to be separately covered with a protection film. That is, there is a possibility that the destruction of the piezoelectric body layer may not be sufficiently suppressed without the protection film.
Such a problem is present not only in the ink jet type recording head, but also in other liquid jet heads ejecting a liquid other than the ink.